Ratchet and Clank: A Crack in Time is the best I’ve played on Ps3.
Some other good ones:
Heavy Rain, Dead Space, The Orange Box (I know it’s on pc of course, but it’s five games for as cheap as $15 now.) AC 2, Little Big Planet, Mirror’s Edge, Borderlands, Split Second, GoW is supposed to be good, but I’ve never played, MGS4 of course (Did you know it’s the only game to ever completely use the full 50gbs on a dual layer bluray?), Infamous, Skate series, ModNation racers, Killzone 2, Resistance 1 and 2.
As for the “Ps3 has no games” joke, I’ve never understood.